Train control



July 24, 1928. 1,678,614

' w. K. HOWE TRAIN common Filed Sept. 6, 1924 ATTORNEY for a turn-out move.

Patented July 24, 1928.

WINTHRO}? K. HOWE, OF ROCHESTER, NEW YORK, assrenos TO mam PATENT; QFMCIQ...

GENERAL RAILWAY SIGNAL COMPANY, or RooHEsTEE, NEW YORK.

TRAIN CONTROL.

Application filed September 6,1924. Serial No. 736,366

This invention relates to automatictrain control systems, and. more specifically to switch protection means for a train control system of the continuous inductive type.

In the usual continuous inductive vtrain control system, the brakes of a train are ap plied or the train speed is in some other way restricted by the lack of control, current 1 which flows in a trackway circuit in the usual insulated blocks of the track rails under clear traflic conditions, and which is out off by suitable means under dangerous traflic conditions ahead. In the usual railway system, points are encountered along the trackway at which a spur track, branch line or siding leaves the main line trackway by means of a track switch, and these track switches when set fora turn-out move,,constitute a dangerous hazard to approaching trafiic. Itis evident that an open track switch in a given block of tlie trackway constitutes a hazard for approaching trains only, and that a train receding from the track switch neednot be under restrictive control.

In view of the above and other considerations, it 1s proposed in accordance with the present invention to provide means operated I in accordance with the posltion of a track,

switch, and acting to cut oil the trackway control current in the portionof an insulated block in the rear of the switch while allow- I ing the control current to flow in the trackway circuit between the track switch and the exit end of the block when the switohis set I Other objects and ad.-

vantages of the present inventionlwill become apparent or will be pointed out as the description progresses. Y

, In the drawings, a section of trackway including a track switch and the protective control means embodying the present invention has been shown, together with a simpli fied and diagrammatic representation of the car-carried apparatus comprising a typical train control system.

Referring particularly to the trackway ap paratus, the track rails 1 are divided into blocks in the usual way by the insulating joints 2, the block I and the ends of the two adjacent blocks H and J having been shown. As the trackway equipment in the adjacent blocks is assumed to be identical, the description of such equipmentin one block only will be given, corresponding elements in the adjacent blocks being referred to by like refer ence characters having distinctive exponents.

Train control current is applied to the two track rails in series at each block from the transformer 3whose primary winding is connected across the transmission line at as shown. The secondary winding of the transformer3 is connected to the track rails through the front contacts oi? fingers 5 and 6 of the track relay 7 and the transformer 8 as clearly shown. The track relay 7 is of the type well known in. railway signaling practice, and in the embodiment shown, is preferably of the direct current type and is connected across the track rails at the entrance end of the block. A track battery 9 is connected across the track rails at the exit end of each block in .series with the secondary winding of the transformer 8 as shown. It; is evident that the track relay 7 will be maintained energized by direct current from the battery 9 flowing in the traclerails when .7

semaphore or any other suitable type may be r employed in connection with the track cirs cuits shown. These wayside signals mayv be,

operated fromth'e track relay 7 in the main ner well known in train control practice. For the purpose of illustration semaphore signals Z havebeen conventionally represented at the entrance end of each block.

Referring now more particularly to the track switch protection meanswhich constitutes the present invention, a typical track; switch S has beenshown in the block I. As; track switches and their operating means are well ,known to those skilled in the art of, railway and signal practice, and as the para ticular switch construction and operating: means used forms no part of the present invention, the track switch S has been shown in a diagrammatic manner only, and it. is assumed that suitable" manual or automatic, operating means are provided. 7 A switch boX S /V is provided adjacent the track Ill) separated by the insulating joints 13. The

switch box contact fingers 11 and 12 are connected to the track rails on either side of the insulating .joints 13 in such a manner that when the track switch S is set for train travel on the main line trackway the insulating joints 13 will be bridged by these contact fingers, and that when the track switch S is set in a position for a turn-out move to the branch line or siding the track rails are divided by the insulating joints 13. It will also be noted that when the track switch S is set for a turn-out move the two track rails 1 in that section of the block preceding the track switch S will be connected by a circuit including the wire let which is connected between two stationary contacts of the switch box contact fingers 11 and 12. This connection between the rails in the entrance portion of the block prevents the leakage of control current from the exit portion of the block past the insulating joints 13 when the track switch is set for a turn-out move.

A railway vehicle has been conventionally represented in the block I by the wheels and axles 15, its normal direction of travelbeing indicated by the arrow. It should be under stood that the railway vehicle may use any suitable type of car-carried train control apparatus for restricting the train speed in accordance with control influences received from the trackway. In the specific embodiment shown for the purpose of illustration, a

type of car-carried control apparatus has been illustrated which acts to apply the brakes of a train or to initiate a restrictive brake application when a section of trackway is traversed in which no control current is present. The simplified car-control apparatus as shown in the drawings employs two receiving coils 16, mounted in front of the leading axles of the vehicle, over and in inductive relation with the track rails. These receiving coils are connected through a circuit which is resonated by the condenser T to an amplifier which has been conventionally represented at A. This amplifier is preferably of the type which employs the usual vacuum tube circuits and which acts to respond .to weak current impulses which has been conventionally represented at BA, may be of any type which is suitable for train control practice, for instance it may causean immediate brake application upon the de-en'ergization of a circuit through its windings, or such de-energizatiton of its windings may initiate suitable mechanism which will set up more restrictive speed limits as the train progresses in dangerous territory. I

V lVith clear trafiic conditions ahead, that is, with no train or other dangerous tralfic condition in a given block, or in the next block in advance, it is evident that control currents flow in series in the track rails and induce currents in the receiving coils 16 of a vehicle in the given block, so maintaining the main relay MR energized and-preventing a restrictive brake application by the energization of the brake control apparatus BA through the contact finger 17 to the main relay MR as clearly shown in the drawings. If, however, the control current is not flowing in the track rails of the given block because of a train in that block shunting the track rails, or by reason of the de-energization of the track relay in the next block in advance due to a trainv or otherdangerous trafiic conditions in such advance block, the receiving coils 16 do notreceive current, the main relay MR is deenergized, and the contact finger 17 0f the main relay is retracted, causing the de-energization of the brake control apparatus BA and a subsequent restrictive brake application.

Now' assume that a train, equipped with the typical brake control. apparatus described, enters the block I in which the track switch S and itsprotective apparatus is located, and that the track switch S is set in a positionfor' train travel. along the main linetrackway. Assuming also that clear t-rafllc conditions exist in the block J,,train control currents are impressed upon the traclrrails in series at the entrance end of the block, pass through the track rails to the open orset for a turn-out move, and that the train under consideration enters the block I; Vfith the track switchin this position, the switchboxccontact fingers 11 and 12 are in the positionsindicated by the dotted lines, the insulating joints13 are no longer bridged and the track rails in that portion of the block preceding the track lt U ceive control currentssfro m the trackrails under this condition and the main relay MB of the car-carried apparatus is de-energized retracting its contact finger 17, 'de-energizing the brake control apparatus BA and causing a restrictive brake application. It is clear that by the use of the: switch protecting apparatus just describedtrainbis prevented from running into the switch set for a turn-out move, at an excessive speed, as far as possible. i

It should be noted that when the track switch S is thrown to the position for a turn-out move to the branch line or siding, that the train control current is in no way interrupted in that section of the block I which lies between the track switch S and theexit end of the block. a train traveling in this exit portion of the block I does notundergo a restrictive brake application when the track switch S is thrown to a position for a turn-out move behind such train. This arrangement avoids unnecessary delays in traflic when the track switch is thrown with a train in the exit portion of the block.

'- train enters into a branch line orother seccomprises the present invention has been described in connection with a rather specific form of train control system, it should be clearly understood that the application of this switch protection means is not limited to the type of control system shown, and

that many additions, modifications and changes could be made in the system shown without departing from the spirit of the present invention. For instance, two sets of receiving coils on the vehicle might be used, responding to two control currents in the track rails; means for reversing the connections to the receiving coils by an automatically or manually operable switch might be shown; or many other changes and combinations might be made.

What it is desired to secure by Letters Patent is:

For this reason 1. A traekway circuit for an automatic train control system comprising a section of track rails containinga, track switch and divided into two portions by insulating oints at said track switch, a source of electrical energy connected across the track rails of one of said portions, a track relay connectedacross the railsol the other of said portions, and means controlled by the position of said track switch for electrically connecting the rails of said portion having a track' relay when the switch is in one positioh,:and for transmitting said electrical energy across said insulating joints when said track switch is in the other position;

2. In an'automatic train control system,

a section of track rails divided into an entrance portion and an exit portion by insulating joints, a track switch adjacent said joints, means for supplying a control current to said exit portion and means controlled the position oi said traok'switch for electrically connecting said two portions when said track switch is in one position and for breaking said connection and connecting the rails of the entrance portion when said track switch is in the other position.

. 3. In an automatic train control swstem, the combination with car-carried apparatus for applying the brakes of a vehicle upon the cessation of control influences normally received from the trackway, a section of track rails containing a track switch leading to a branch trackway, said section being 7 divided into an entrance portion and an exit portion by insulating joints adjacent said track switch, means for supplying the cur rent for producing said control influences to said exit portion under favorable traific conditions ahead, and means actuated by the movement of saidtrack switch for bridging said insulating joints and so transmitting said current to the entire section when said track switch is set for vehicle travel along said section, and for disconnecting said portions and electrically connecting the rails of said entranceportion when said track switch is set for vehicle travel on said branch trackway, whereby a brake application will be effected on a vehicle in said entrance portion when said track switch is set for vehicle travel on said branch trackway.

a. The combination with a main railway track divided into blocks by insulating joints, a source of alternating current for train control purposesconnected across the track rails at the exit end of each block, a track switch leading to a diverging trackway located at an intermediate point in a block between two successive signals, insulating joints in the main track at said track switch, and ,means for bridging said insulating joints only when said track switch is set for train travel along the main track.

5. In combination Wth a railway track entrance end of each block, a source of signaling current connected across the track rails at the exit end of each block, a track switch at an intermediate point in a block leading to a diverging trackway, an insulating joint in each track rail adjacent said track switch and a circuit controller mechanically connected to and operated by said track switch acting to bridge each of said last mentioned insulating joints when said track switch is set for train travel along the main track but which leaves said last mentioned insulating joints unbridged when said track switch is set for train travel over said diverging trackway.

6. Trackway apparatus for train control purposes for train control systems of the continuous inductive type in which a train is permitted to proceed in response to train control current flowing in the two track rails in series and detected on the train comprising atrack dividedinto blocks by insulating j oints; a track relay at the entrance end of each block 'a source of signalling current connected across the track rails at the exit end of each block, a source of train control current connectedin series with said source of signalling current, a track'switch leading to a diverging trackway located at an intermediate, point in a block, and means for interrupting the electrical continuity of the track rails at said intermediate point when said track switch is set, for train travel over said diverging trackway, whereby the track relay at the entrance end ofgsaid block is tie-energized and no train control current can he detectedin the rear of said track switch, whereas traincontrolcurrent can be detected by a train traveling in said block ahead of said tracksWitch when said switch is'set for train travel over said diverging trackway. c

In testimony whereof I aflix my signature.

WINTHROP K. HOWE. 

